1. Field of the Invention
The present invention relates to an automatic clutch control device that automatically connects/disconnects a clutch disposed between an output shaft of a power source of a vehicle and an input shaft of a transmission of the vehicle.
2. Description of the Prior Arts
There has conventionally been known an automatic clutch control device provided with a clutch connecting/disconnecting actuator for driving a clutch, disposed between an output shaft of a power source of a vehicle and an input shaft of a transmission, so as to be connected and disconnected, wherein, not by an operation of a clutch pedal by a driver but by the clutch connecting/disconnecting actuator, a disconnecting operation for changing the state of the clutch from a connecting state to a disconnecting state is executed before the transmission starts the shift operation and a connecting operation for changing the state of the clutch from the disconnecting state to the connecting state is executed after the shift operation is completed (for example, see the following patent documents 1 and 2).
Further, the patent documents 1 and 2 described below disclose a technique for preventing the occurrence of a stall of an engine by changing the state of the clutch to a half-connecting state (sometimes referred to as “half-clutch state” in this specification) or a disconnecting state regardless of the shift operation of the transmission, when the clutch is in a connecting state and a vehicle body speed is not more than a predetermined speed (e.g., 5 km/h).
[Patent Document 1]
Japanese Unexamined Patent Application No. SHO60-44641
[Patent Document 1]
Japanese Unexamined Patent Application No. HEI9-79374
However, even when a vehicle body speed is great to some degree, there may be a case where the driving wheel is locked to cause an engine stall when, for example, braking force by an engine brake is caused on the driving wheel during when a vehicle is running on a road having a small road friction coefficient. In this case too, it is preferable to bring the clutch into the half-connecting state or the disconnecting state regardless of the shift operation of the transmission.
In other words, even when there is a demand to change the state of the clutch to the half-connecting state or to the disconnecting state regardless of the shift operation of the transmission according to various running states of the vehicle when the clutch is in the connecting state, the conventional device disclosed in the above-mentioned patent documents 1 and 2 has a problem that the state of the clutch cannot suitably be changed to the half-connecting state or the disconnecting state according to the demand.